The isolation, determination of structure, and quantitation of tannins have been exhaustively investigated because of concerns with their possible physiological effects and because of their interest as pharmaceutical agents. The separation of closely related oligomers has been accomplished with droplet countercurrent and centrifugal partition chromatography (17). By use of these techniques, large molecules, such as nobotanin K, consisting of 4 glucose and 20 gallic acid groups have been isolated in the pure state. Accurate molecular mass determination of these nonvolatile substances has been perfected with the use of fast atomic bombardment (FAB) and mass spectrometry (MS). Nuclear magnetic resonance (NMR) spectroscopy has also provided details of the intricate molecular structures of large complex species. The use of fast atom bombardment mass spectrometry (FABMS) has allowed for the accurate structure determination of large tannin molecules—up to molecular weight of 3200 (18). The most significant methods for the quantitation of tannins are based on measurements of protein precipitation, since their most important properties are attributed to this effect. Procedures based on interaction with bovine serum albumen measure both tannins and protein in the precipitate (19). As little of 5 fig of tannic acid can be detected.

Sleeping Sanctuary

Sleeping Sanctuary

Salvation For The Sleep Deprived The Ultimate Guide To Sleeping, Napping, Resting And  Restoring Your Energy. Of the many things that we do just instinctively and do not give much  of a thought to, sleep is probably the most prominent one. Most of us sleep only because we have to. We sleep because we cannot stay awake all 24 hours in the day.

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